Buggy code:
int getPartialBottomIndex ( ) { } int getPartialTopIndex ( ) { } String getPlatformDelimitedText ( StyledText . TextWriter writer ) { } public int [ ] getRanges ( ) { } public int [ ] getRanges ( int start , int length ) { } public int getRightMargin ( ) { } public Point getSelection ( ) { } public Point getSelectionRange ( ) { } public int [ ] getSelectionRanges ( ) { } public Color getSelectionBackground ( ) { } public int getSelectionCount ( ) { } public Color getSelectionForeground ( ) { } public String getSelectionText ( ) { } public int getStyle ( ) { } int [ ] getBidiSegments ( int lineOffset , String line ) { } int [ ] getBidiSegmentsCompatibility ( String line , int lineOffset ) { } public StyleRange getStyleRangeAtOffset ( int offset ) { } public StyleRange [ ] getStyleRanges ( ) { } public StyleRange [ ] getStyleRanges ( boolean includeRanges ) { } public StyleRange [ ] getStyleRanges ( int start , int length ) { } public StyleRange [ ] getStyleRanges ( int start , int length , boolean includeRanges ) { } public int getTabs ( ) { } public String getText ( ) { } public String getText ( int start , int end ) { } public Rectangle getTextBounds ( int start , int end ) { } public String getTextRange ( int start , int length ) { } public int getTextLimit ( ) { } public int getTopIndex ( ) { } public int getTopMargin ( ) { } public int getTopPixel ( ) { } int getVerticalIncrement ( ) { } int getVerticalScrollOffset ( ) { } int getVisualLineIndex ( TextLayout layout , int offsetInLine ) { } int getCaretDirection ( ) { } int getCaretLine ( ) { } int getWrapWidth ( ) { } int getWordNext ( int offset , int movement ) { } int getWordPrevious ( int offset , int movement ) { } public boolean getWordWrap ( ) { } Point getPointAtOffset ( int offset ) { } public void insert ( String string ) { } int insertBlockSelectionText ( String text , boolean fillWithSpaces ) { } void insertBlockSelectionText ( char key , int action ) { } void installDefaultContent ( ) { } void installListeners ( ) { } void internalRedrawRange ( int start , int length ) { } void handleCompositionOffset ( Event event ) { } void handleCompositionSelection ( Event event ) { } void handleCompositionChanged ( Event event ) { } void handleDispose ( Event event ) { } void handleHorizontalScroll ( Event event ) { } void handleKey ( Event event ) { int action ; caretAlignment = StyledText . PREVIOUS_OFFSET_TRAILING ; if ( ( event . keyCode ) != 0 ) { action = getKeyBinding ( ( ( event . keyCode ) | ( event . stateMask ) ) ) ; } else { action = getKeyBinding ( ( ( event . character ) | ( event . stateMask ) ) ) ; if ( action == ( SWT . NULL ) ) { <START_BUG> if ( ( ( ( ( event . stateMask ) & ( SWT . CTRL ) ) != 0 ) && ( ( event . character ) >= 0 ) ) && ( ( event . character ) <= 31 ) ) { <END_BUG> int c = ( event . character ) + 64 ; action = getKeyBinding ( ( c | ( event . stateMask ) ) ) ; } } } if ( action == ( SWT . NULL ) ) { boolean ignore = false ; if ( StyledText . IS_MAC ) { ignore = ( ( ( event . stateMask ) ^ ( SWT . COMMAND ) ) == 0 ) || ( ( ( event . stateMask ) ^ ( ( SWT . COMMAND ) | ( SWT . SHIFT ) ) ) == 0 ) ; } else if ( StyledText . IS_MOTIF ) { ignore = ( ( ( event . stateMask ) ^ ( SWT . CTRL ) ) == 0 ) || ( ( ( event . stateMask ) ^ ( ( SWT . CTRL ) | ( SWT . SHIFT ) ) ) == 0 ) ; } else { ignore = ( ( ( ( ( event . stateMask ) ^ ( SWT . ALT ) ) == 0 ) || ( ( ( event . stateMask ) ^ ( SWT . CTRL ) ) == 0 ) ) || ( ( ( event . stateMask ) ^ ( ( SWT . ALT ) | ( SWT . SHIFT ) ) ) == 0 ) ) || ( ( ( event . stateMask ) ^ ( ( SWT . CTRL ) | ( SWT . SHIFT ) ) ) == 0 ) ; } if ( ( ( ( ( ( ! ignore ) && ( ( event . character ) > 31 ) ) && ( ( event . character ) != ( SWT . DEL ) ) ) || ( ( event . character ) == ( SWT . CR ) ) ) || ( ( event . character ) == ( SWT . LF ) ) ) || ( ( event . character ) == ( StyledText . TAB ) ) ) { doContent ( event . character ) ; update ( ) ; } } else { invokeAction ( action ) ; } } void handleKeyDown ( Event event ) { } void handleKeyUp ( Event event ) { } void handleMouseDown ( Event event ) { } void handleMouseMove ( Event event ) { } void handleMouseUp ( Event event ) { } void handlePaint ( Event event ) { } void handleResize ( Event event ) { } void handleTextChanged ( TextChangedEvent event ) { } void handleTextChanging ( TextChangingEvent event ) { }

Fix:
if ( ( ( ( event . stateMask ) & ( SWT . CTRL ) ) != 0 ) && ( ( event . character ) <= 31 ) ) {